Magnetic Circular Dichroism and Electronic Absorption Spectra of Mixed (Amine)(carboxylato) Complexes with the [Pd(N)n(O)4–n]-type (n=0–4)

Abstract

Abstract Mixed-ligand [Pd(N)n(O)4–n]-type complexes constituting a long systematic series (n=0–4) were synthesized. Ammonia, ethylenediamine, rac-propylenediamine, trimethylenediamine, glycinate, β-alaninate, acetate, oxalate, and malonate were employed as ligands. Their magnetic circular dichroism (MCD) and electronic absorption spectra were discussed together with the CD spectra of the corresponding optically active complexes. The results strongly suggest that the dispersion of MCD observed in the spin-allowed d-d region is primarily a composite of B terms. Moreover, the MCD in the charge transfer region was found to be qualitatively additive with respect to contributions by the constituent ligands. From a detailed examination of the spin-allowed d-d absorption bands, it is noted that the substitution of an N,O-ligand for an N,N-ligand largely affects neither the band area nor band width whereas that of an O,O-ligand for an N,O-ligand does.